Cell surface receptor that plays a role in various physiological processes including inflammation, phagocytosis, and cell adhesion. Plays a role in phagocytosis and enhances the uptake of apoptotic cells and immune complexes by acting as a receptor for defense collagens including surfactant protein A/SFTPA1, C1q, and mannose-binding lectin (MBL2) (PubMed:7977768). Plays a role in the regulation of endothelial cell function and adhesion by activating angiogenesis (PubMed:24809468). Mechanistically, exerts its angiogenic function by associating with beta-dystroglycan, leading to SRC- dependent phosphorylation and subsequent recruitment of CBL. In turn, CBL provides a docking site for downstream signaling components, such as CRKL to enhance cell migration (PubMed:26848865). Participates in angiogenesis also by acting as a receptor for the ECM pan-endothelial glycoprotein multimerin-2/MMRN2 and IGFBP7 ligands (PubMed:28671670, PubMed:36265539, PubMed:38218180). Both ligands play a non-redundant role in CD93-mediated endothelial cell function (PubMed:38218180). Acts as a key regulator of endothelial barrier function through modulating VEGFR2 function (By similarity). {ECO:0000250|UniProtKB:O89103, ECO:0000269|PubMed:24809468, ECO:0000269|PubMed:26848865, ECO:0000269|PubMed:28671670, ECO:0000269|PubMed:36265539, ECO:0000269|PubMed:38218180, ECO:0000269|PubMed:7977768}. This is the function of CD93 (CD93 molecule, ENSG00000125810).